You can definitely practice sports during lucid dreaming. You can check out Dr. Daniel Erlachers Dissertation "motorisches Lernen im luziden Traum" which has one chapter about Prof. Paul Tholey, the German lucid dreaming pioneer.
He intensively practiced sports during lucid dreaming. E.g. he started skateboarding in 1978 and became European Champion in 1979.
He was also a great snowboarder, doing a handstand riding a snowboard.